Adding untrusted crash dump / stack trace tests.

src/untrusted/crash_dump/decode_dump.py

Index: src/untrusted/crash_dump/decode_dump.py
diff --git a/src/untrusted/crash_dump/decode_dump.py b/src/untrusted/crash_dump/decode_dump.py
new file mode 100755
index 0000000000000000000000000000000000000000..62491f9cb3e4a9bde8a733b2559b308466fb49d8
--- /dev/null
+++ b/src/untrusted/crash_dump/decode_dump.py
@@ -0,0 +1,197 @@
+#!/usr/bin/python
+# Copyright (c) 2012 The Native Client Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utility to decode a crash dump generated by untrusted_crash_dump.[ch]
+
+Currently this produces a simple stack trace.
+"""
+
+import json
+import optparse
+import os
+import posixpath
+import subprocess
+import sys
+
+
+class CoreDecoder(object):
+  """Class to process core dumps."""
+
+  def __init__(self, main_nexe, nmf_filename,
+               addr2line, toolchain_libs):
+    """Construct and object to process core dumps.
+
+    Args:
+      main_nexe: nexe to resolve NaClMain references from.
+      nmf_filename: nmf to resovle references from.
+      addr2line: path to appropriate addr2line.
+      toolchain_libs: path to the toolchain libraries.
+    """
+    self.main_nexe = main_nexe
+    self.nmf_filename = nmf_filename
+    if nmf_filename == '-':
+      self.nmf_data = {}
+    else:
+      self.nmf_data = json.load(open(nmf_filename))
+    self.addr2line = addr2line
+    self.toolchain_libs = toolchain_libs
+
+  def _SelectModulePath(self, filename):
+    """Select which path to get a module from.
+
+    Args:
+      filename: filename of a module (as appears in phdrs).
+    Returns:
+      Full local path to the file.
+      Derived by consulting the manifest.
+    """
+    # For some names try the main nexe.
+    # NaClMain is the argv[0] setup in sel_main.c
+    # (null) shows up in chrome.
+    if self.main_nexe is not None and filename in ['NaClMain', '(null)']:
+      return self.main_nexe
+    filepart = posixpath.basename(filename)
+    nmf_entry = self.nmf_data.get('files', {}).get(filepart, {})
+    # TODO(bradnelson): support x86-64 + arm.
+    nmf_url = nmf_entry.get('x86-32', {}).get('url')
+    # Try filename directly if not in manifest.
+    if nmf_url is None:
+      return filename
+    # Look for the module relative to the manifest (if any), then toolchain.
+    paths = []
+    if self.nmf_filename != '-':
+      paths.append(os.path.dirname(self.nmf_filename))
+    if self.toolchain_libs is not None:
+      paths.append(self.toolchain_libs)
+    for path in paths:
+      pfilename = os.path.join(path, nmf_url)
+      if os.path.exists(pfilename):
+        return pfilename
+    # If nothing else, try the path directly.
+    return filename
+
+  def _DecodeAddressSegment(self, segments, address):
+    """Convert an address to a segment relative one, plus filename.
+
+    Args:
+      segments: a list of phdr segments.
+      address: a process wide code address.
+    Returns:
+      A tuple of filename and segment relative address.
+    """
+    for segment in segments:
+      for phdr in segment['dlpi_phdr']:
+        start = segment['dlpi_addr'] + phdr['p_vaddr']
+        end = start + phdr['p_memsz']
+        if address >= start and address < end:
+          return (segment['dlpi_name'], address - segment['dlpi_addr'])
+    return ('(null)', address)
+
+  def _Addr2Line(self, segments, address):
+    """Use addr2line to decode a code address.
+
+    Args:
+      segments: A list of phdr segments.
+      address: a code address.
+    Returns:
+      A list of dicts containing: function, filename, lineno.
+    """
+    filename, address = self._DecodeAddressSegment(segments, address)
+    filename = self._SelectModulePath(filename)
+    if not os.path.exists(filename):
+      return [{
+          'function': 'Unknown_function',
+          'filename': 'unknown_file',
+          'lineno': -1,
+      }]
+    # Use address - 1 to get the call site instead of the line after.
+    address -= 1
+    cmd = [
+        self.addr2line, '-f', '--inlines', '-e', filename, '0x%08x' % address,
+    ]
+    process = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    process_stdout, _ = process.communicate()
+    assert process.returncode == 0
+    lines = process_stdout.splitlines()
+    assert len(lines) % 2 == 0
+    results = []
+    for index in xrange(len(lines) / 2):
+      func = lines[index * 2]
+      afilename, lineno = lines[index * 2 + 1].split(':', 1)
+      results.append({
+          'function': func,
+          'filename': afilename,
+          'lineno': int(lineno),
+      })
+    return results
+
+  def LoadAndDecode(self, core_path):
+    """Given a core.json file, load and embellish with decoded addresses.
+
+    Args:
+      core_path: source file containing a dump.
+    Returns:
+      An embelished core dump dict (decoded code addresses).
+    """
+    core = json.load(open(core_path))
+    for frame in core['frames']:
+      frame['scopes'] = self._Addr2Line(core['segments'], frame['prog_ctr'])
+    return core
+
+  def StackTrace(self, info):
+    """Convert a decoded core.json dump to a simple stack trace.
+
+    Args:
+      info: core.json info with decoded code addresses.
+    Returns:
+      A list of dicts with filename, lineno, function (deepest first).
+    """
+    trace = []
+    for frame in info['frames']:
+      for scope in frame['scopes']:
+        trace.append(scope)
+    return trace
+
+  def PrintTrace(self, trace, out):
+    """Print a trace to a file like object.
+
+    Args:
+      trace: A list of [filename, lineno, function] (deepest first).
+      out: file like object to output the trace to.
+    """
+    for scope in trace:
+      out.write('%s at %s:%d\n' % (
+          scope['function'],
+          scope['filename'],
+          scope['lineno']))
+
+
+def Main(args):
+  parser = optparse.OptionParser(
+      usage='USAGE: %prog [options] <core.json>')
+  parser.add_option('-m', '--main-nexe', dest='main_nexe',
+                    help='nexe to resolve NaClMain references from')
+  parser.add_option('-n', '--nmf', dest='nmf_filename', default='-',
+                    help='nmf to resolve references from')
+  parser.add_option('-a', '--addr2line', dest='addr2line',
+                    help='path to appropriate addr2line')
+  parser.add_option('-l', '--toolchain-libs', dest='toolchain_libs',
+                    help='path to the toolchain libraries')
+  options, args = parser.parse_args(args)
+  if len(args) != 1:
+    parser.print_help()
+    sys.exit(1)
+  decoder = CoreDecoder(
+      main_nexe=options.main_nexe,
+      nmf_filename=options.nmf_filename,
+      addr2line=options.add2line,
+      toolchain_libs=options.toolchain_libs)
+  info = decoder.LoadAndDecode(args[0])
+  trace = decoder.StackTrace(info)
+  decoder.PrintTrace(trace, sys.stdout)
+
+
+if __name__ == '__main__':
+  Main(sys.argv[1:])